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Time.javaAPI DocAndroid 1.5 API27721Wed May 06 22:41:56 BST 2009android.text.format

Time

public class Time extends Object
The Time class is a faster replacement for the java.util.Calendar and java.util.GregorianCalendar classes. An instance of the Time class represents a moment in time, specified with second precision. It is modelled after struct tm, and in fact, uses struct tm to implement most of the functionality.

Fields Summary
private static final String
Y_M_D_T_H_M_S_000
private static final String
Y_M_D_T_H_M_S_000_Z
private static final String
Y_M_D
public static final String
TIMEZONE_UTC
public static final int
EPOCH_JULIAN_DAY
The Julian day of the epoch, that is, January 1, 1970 on the Gregorian calendar.
public boolean
allDay
True if this is an allDay event. The hour, minute, second fields are all zero, and the date is displayed the same in all time zones.
public int
second
Seconds [0-61] (2 leap seconds allowed)
public int
minute
Minute [0-59]
public int
hour
Hour of day [0-23]
public int
monthDay
Day of month [1-31]
public int
month
Month [0-11]
public int
year
Year. TBD. Is this years since 1900 like in struct tm?
public int
weekDay
Day of week [0-6]
public int
yearDay
Day of year [0-365]
public int
isDst
This time is in daylight savings time. One of:
  • positive - in dst
  • 0 - not in dst
  • negative - unknown
public long
gmtoff
Offset from UTC (in seconds).
public String
timezone
The timezone for this Time. Should not be null.
public static final int
SECOND
public static final int
MINUTE
public static final int
HOUR
public static final int
MONTH_DAY
public static final int
MONTH
public static final int
YEAR
public static final int
WEEK_DAY
public static final int
YEAR_DAY
public static final int
WEEK_NUM
public static final int
SUNDAY
public static final int
MONDAY
public static final int
TUESDAY
public static final int
WEDNESDAY
public static final int
THURSDAY
public static final int
FRIDAY
public static final int
SATURDAY
private static Locale
sLocale
private static String[]
sShortMonths
private static String[]
sLongMonths
private static String[]
sShortWeekdays
private static String[]
sLongWeekdays
private static String
sTimeOnlyFormat
private static String
sDateOnlyFormat
private static String
sDateTimeFormat
private static String
sAm
private static String
sPm
private static String
sDateCommand
private static final int[]
DAYS_PER_MONTH
private static final int[]
sThursdayOffset
This array is indexed by the weekDay field (SUNDAY=0, MONDAY=1, etc.) and gives a number that can be added to the yearDay to give the closest Thursday yearDay.
Constructors Summary
public Time(String timezone)
Construct a Time object in the timezone named by the string argument "timezone". The time is initialized to Jan 1, 1970.

param
timezone string containing the timezone to use.
see
TimeZone


                                        
       
        if (timezone == null) {
            throw new NullPointerException("timezone is null!");
        }
        this.timezone = timezone;
        this.year = 1970;
        this.monthDay = 1;
        // Set the daylight-saving indicator to the unknown value -1 so that
        // it will be recomputed.
        this.isDst = -1;
public Time()
Construct a Time object in the default timezone. The time is initialized to Jan 1, 1970.

        this(TimeZone.getDefault().getID());
public Time(Time other)
A copy constructor. Construct a Time object by copying the given Time object. No normalization occurs.

param
other

        set(other);
Methods Summary
public booleanafter(android.text.format.Time that)
Returns true if the time represented by this Time object occurs after the given time.

param
that a given Time object to compare against
return
true if this time is greater than the given time

        return Time.compare(this, that) > 0;
public booleanbefore(android.text.format.Time that)
Returns true if the time represented by this Time object occurs before the given time.

param
that a given Time object to compare against
return
true if this time is less than the given time

        return Time.compare(this, that) < 0;
public voidclear(java.lang.String timezone)
Clears all values, setting the timezone to the given timezone. Sets isDst to a negative value to mean "unknown".

param
timezone the timezone to use.

        if (timezone == null) {
            throw new NullPointerException("timezone is null!");
        }
        this.timezone = timezone;
        this.allDay = false;
        this.second = 0;
        this.minute = 0;
        this.hour = 0;
        this.monthDay = 0;
        this.month = 0;
        this.year = 0;
        this.weekDay = 0;
        this.yearDay = 0;
        this.gmtoff = 0;
        this.isDst = -1;
public static native intcompare(android.text.format.Time a, android.text.format.Time b)
return a negative number if a is less than b, a positive number if a is greater than b, and 0 if they are equal.

public java.lang.Stringformat(java.lang.String format)
Print the current value given the format string provided. See man
strftime for what means what. The final string must be less than 256
characters.
param
format a string containing the desired format.
return
a String containing the current time expressed in the current locale.
        synchronized (Time.class) {
            Locale locale = Locale.getDefault();

            if (sLocale == null || locale == null || !(locale.equals(sLocale))) {
                Resources r = Resources.getSystem();

                sShortMonths = new String[] {
                    r.getString(com.android.internal.R.string.month_medium_january),
                    r.getString(com.android.internal.R.string.month_medium_february),
                    r.getString(com.android.internal.R.string.month_medium_march),
                    r.getString(com.android.internal.R.string.month_medium_april),
                    r.getString(com.android.internal.R.string.month_medium_may),
                    r.getString(com.android.internal.R.string.month_medium_june),
                    r.getString(com.android.internal.R.string.month_medium_july),
                    r.getString(com.android.internal.R.string.month_medium_august),
                    r.getString(com.android.internal.R.string.month_medium_september),
                    r.getString(com.android.internal.R.string.month_medium_october),
                    r.getString(com.android.internal.R.string.month_medium_november),
                    r.getString(com.android.internal.R.string.month_medium_december),
                };
                sLongMonths = new String[] {
                    r.getString(com.android.internal.R.string.month_long_january),
                    r.getString(com.android.internal.R.string.month_long_february),
                    r.getString(com.android.internal.R.string.month_long_march),
                    r.getString(com.android.internal.R.string.month_long_april),
                    r.getString(com.android.internal.R.string.month_long_may),
                    r.getString(com.android.internal.R.string.month_long_june),
                    r.getString(com.android.internal.R.string.month_long_july),
                    r.getString(com.android.internal.R.string.month_long_august),
                    r.getString(com.android.internal.R.string.month_long_september),
                    r.getString(com.android.internal.R.string.month_long_october),
                    r.getString(com.android.internal.R.string.month_long_november),
                    r.getString(com.android.internal.R.string.month_long_december),
                };
                sShortWeekdays = new String[] {
                    r.getString(com.android.internal.R.string.day_of_week_medium_sunday),
                    r.getString(com.android.internal.R.string.day_of_week_medium_monday),
                    r.getString(com.android.internal.R.string.day_of_week_medium_tuesday),
                    r.getString(com.android.internal.R.string.day_of_week_medium_wednesday),
                    r.getString(com.android.internal.R.string.day_of_week_medium_thursday),
                    r.getString(com.android.internal.R.string.day_of_week_medium_friday),
                    r.getString(com.android.internal.R.string.day_of_week_medium_saturday),
                };
                sLongWeekdays = new String[] {
                    r.getString(com.android.internal.R.string.day_of_week_long_sunday),
                    r.getString(com.android.internal.R.string.day_of_week_long_monday),
                    r.getString(com.android.internal.R.string.day_of_week_long_tuesday),
                    r.getString(com.android.internal.R.string.day_of_week_long_wednesday),
                    r.getString(com.android.internal.R.string.day_of_week_long_thursday),
                    r.getString(com.android.internal.R.string.day_of_week_long_friday),
                    r.getString(com.android.internal.R.string.day_of_week_long_saturday),
                };
                sTimeOnlyFormat = r.getString(com.android.internal.R.string.time_of_day);
                sDateOnlyFormat = r.getString(com.android.internal.R.string.month_day_year);
                sDateTimeFormat = r.getString(com.android.internal.R.string.date_and_time);
                sAm = r.getString(com.android.internal.R.string.am);
                sPm = r.getString(com.android.internal.R.string.pm);

                sLocale = locale;
            }

            return format1(format);
        }
    
private native java.lang.Stringformat1(java.lang.String format)
public native java.lang.Stringformat2445()
Format according to RFC 2445 DATETIME type.



The same as format("%Y%m%dT%H%M%S").
public java.lang.Stringformat3339(boolean allDay)
Return a string in the RFC 3339 format.


If allDay is true, expresses the time as Y-M-D



Otherwise, if the timezone is UTC, expresses the time as Y-M-D-T-H-M-S UTC



Otherwise the time is expressed the time as Y-M-D-T-H-M-S +- GMT
param
allDay
return
string in the RFC 3339 format.
        if (allDay) {
            return format(Y_M_D);
        } else if (TIMEZONE_UTC.equals(timezone)) {
            return format(Y_M_D_T_H_M_S_000_Z);
        } else {
            String base = format(Y_M_D_T_H_M_S_000);
            String sign = (gmtoff < 0) ? "-" : "+";
            int offset = (int)Math.abs(gmtoff);
            int minutes = (offset % 3600) / 60;
            int hours = offset / 3600;
            
            return String.format("%s%s%02d:%02d", base, sign, hours, minutes);
        }
    
public intgetActualMaximum(int field)
Return the maximum possible value for the given field given the value of
the other fields. Requires that it be normalized for MONTH_DAY and
YEAR_DAY.
param
field one of the constants for HOUR, MINUTE, SECOND, etc.
return
the maximum value for the field.

                                                    
        
        switch (field) {
        case SECOND:
            return 59; // leap seconds, bah humbug
        case MINUTE:
            return 59;
        case HOUR:
            return 23;
        case MONTH_DAY: {
            int n = DAYS_PER_MONTH[this.month];
            if (n != 28) {
                return n;
            } else {
                int y = this.year;
                return ((y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0)) ? 29 : 28;
            }
        }
        case MONTH:
            return 11;
        case YEAR:
            return 2037;
        case WEEK_DAY:
            return 6;
        case YEAR_DAY: {
            int y = this.year;
            // Year days are numbered from 0, so the last one is usually 364.
            return ((y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0)) ? 365 : 364;
        }
        case WEEK_NUM:
            throw new RuntimeException("WEEK_NUM not implemented");
        default:
            throw new RuntimeException("bad field=" + field);
        }
    
public static java.lang.StringgetCurrentTimezone()
Returns the timezone string that is currently set for the device.
        return TimeZone.getDefault().getID();
    
public static intgetJulianDay(long millis, long gmtoff)
Computes the Julian day number, given the UTC milliseconds
and the offset (in seconds) from UTC. The Julian day for a given
date will be the same for every timezone. For example, the Julian
day for July 1, 2008 is 2454649. This is the same value no matter
what timezone is being used. The Julian day is useful for testing
if two events occur on the same day and for determining the relative
time of an event from the present ("yesterday", "3 days ago", etc.).



Use {@link #toMillis(boolean)} to get the milliseconds.
param
millis the time in UTC milliseconds
param
gmtoff the offset from UTC in seconds
return
the Julian day
        long offsetMillis = gmtoff * 1000;
        long julianDay = (millis + offsetMillis) / DateUtils.DAY_IN_MILLIS;
        return (int) julianDay + EPOCH_JULIAN_DAY;
    
public intgetWeekNumber()
Computes the week number according to ISO 8601. The current Time
object must already be normalized because this method uses the
yearDay and weekDay fields.



In IS0 8601, weeks start on Monday.
The first week of the year (week 1) is defined by ISO 8601 as the
first week with four or more of its days in the starting year.
Or equivalently, the week containing January 4. Or equivalently,
the week with the year's first Thursday in it.





The week number can be calculated by counting Thursdays. Week N
contains the Nth Thursday of the year.

return
the ISO week number.
        
                                                                                                                          
       
        // Get the year day for the closest Thursday
        int closestThursday = yearDay + sThursdayOffset[weekDay];

        // Year days start at 0
        if (closestThursday >= 0 && closestThursday <= 364) {
            return closestThursday / 7 + 1;
        }
        
        // The week crosses a year boundary.
        Time temp = new Time(this);
        temp.monthDay += sThursdayOffset[weekDay];
        temp.normalize(true /* ignore isDst */);
        return temp.yearDay / 7 + 1;
    
public static booleanisEpoch(android.text.format.Time time)
Returns true if the day of the given time is the epoch on the Julian Calendar
(January 1, 1970 on the Gregorian calendar).
param
time the time to test
return
true if epoch.
        long millis = time.toMillis(true);
        return getJulianDay(millis, 0) == EPOCH_JULIAN_DAY;
    
private native booleannativeParse(java.lang.String s)
Parse a time in the current zone in YYYYMMDDTHHMMSS format.
private native booleannativeParse3339(java.lang.String s)
public native longnormalize(boolean ignoreDst)
Ensures the values in each field are in range. For example if the
current value of this calendar is March 32, normalize() will convert it
to April 1. It also fills in weekDay, yearDay, isDst and gmtoff.



If "ignoreDst" is true, then this method sets the "isDst" field to -1
(the "unknown" value) before normalizing. It then computes the
correct value for "isDst".



See {@link #toMillis(boolean)} for more information about when to
use true or false for "ignoreDst".
return
the UTC milliseconds since the epoch
public booleanparse(java.lang.String s)
Parses a date-time string in either the RFC 2445 format or an abbreviated
format that does not include the "time" field. For example, all of the
following strings are valid:


    

  • "20081013T160000Z"
    • 

  • "20081013T160000"
    • 

  • "20081013"
    • 



Returns whether or not the time is in UTC (ends with Z). If the string
ends with "Z" then the timezone is set to UTC. If the date-time string
included only a date and no time field, then the allDay
field of this Time class is set to true and the hour,
minute, and second fields are set to zero;
otherwise (a time field was included in the date-time string)
allDay is set to false. The fields weekDay,
yearDay, and gmtoff are always set to zero,
and the field isDst is set to -1 (unknown). To set those
fields, call {@link #normalize(boolean)} after parsing.

To parse a date-time string and convert it to UTC milliseconds, do
something like this:


Time time = new Time();
String date = "20081013T160000Z";
time.parse(date);
long millis = time.normalize(false);

param
s the string to parse
return
true if the resulting time value is in UTC time
throws
android.util.TimeFormatException if s cannot be parsed.
        if (nativeParse(s)) {
            timezone = TIMEZONE_UTC;
            return true;
        }
        return false;
    
public booleanparse3339(java.lang.String s)
Parse a time in RFC 3339 format. This method also parses simple dates
(that is, strings that contain no time or time offset). For example,
all of the following strings are valid:


    

  • "2008-10-13T16:00:00.000Z"
    • 

  • "2008-10-13T16:00:00.000+07:00"
    • 

  • "2008-10-13T16:00:00.000-07:00"
    • 

  • "2008-10-13"
    • 





If the string contains a time and time offset, then the time offset will
be used to convert the time value to UTC.





If the given string contains just a date (with no time field), then
the {@link #allDay} field is set to true and the {@link #hour},
{@link #minute}, and {@link #second} fields are set to zero.





Returns true if the resulting time value is in UTC time.

param
s the string to parse
return
true if the resulting time value is in UTC time
         if (nativeParse3339(s)) {
             timezone = TIMEZONE_UTC;
             return true;
         }
         return false;
     
public native voidset(long millis)
Sets the fields in this Time object given the UTC milliseconds. After
this method returns, all the fields are normalized.
This also sets the "isDst" field to the correct value.
param
millis the time in UTC milliseconds since the epoch.
public voidset(android.text.format.Time that)
Copy the value of that to this Time object. No normalization happens.
        this.timezone = that.timezone;
        this.allDay = that.allDay;
        this.second = that.second;
        this.minute = that.minute;
        this.hour = that.hour;
        this.monthDay = that.monthDay;
        this.month = that.month;
        this.year = that.year;
        this.weekDay = that.weekDay;
        this.yearDay = that.yearDay;
        this.isDst = that.isDst;
        this.gmtoff = that.gmtoff;
    
public voidset(int second, int minute, int hour, int monthDay, int month, int year)
Sets the fields. Sets weekDay, yearDay and gmtoff to 0, and isDst to -1.
Call {@link #normalize(boolean)} if you need those.
        this.allDay = false;
        this.second = second;
        this.minute = minute;
        this.hour = hour;
        this.monthDay = monthDay;
        this.month = month;
        this.year = year;
        this.weekDay = 0;
        this.yearDay = 0;
        this.isDst = -1;
        this.gmtoff = 0;
    
public voidset(int monthDay, int month, int year)
Sets the date from the given fields. Also sets allDay to true.
Sets weekDay, yearDay and gmtoff to 0, and isDst to -1.
Call {@link #normalize(boolean)} if you need those.
param
monthDay the day of the month (in the range [1,31])
param
month the zero-based month number (in the range [0,11])
param
year the year
        this.allDay = true;
        this.second = 0;
        this.minute = 0;
        this.hour = 0;
        this.monthDay = monthDay;
        this.month = month;
        this.year = year;
        this.weekDay = 0;
        this.yearDay = 0;
        this.isDst = -1;
        this.gmtoff = 0;
    
public longsetJulianDay(int julianDay)
Sets the time from the given Julian day number, which must be based on
the same timezone that is set in this Time object. The "gmtoff" field
need not be initialized because the given Julian day may have a different
GMT offset than whatever is currently stored in this Time object anyway.
After this method returns all the fields will be normalized and the time
will be set to 12am at the beginning of the given Julian day.





The only exception to this is if 12am does not exist for that day because
of daylight saving time. For example, Cairo, Eqypt moves time ahead one
hour at 12am on April 25, 2008 and there are a few other places that
also change daylight saving time at 12am. In those cases, the time
will be set to 1am.

param
julianDay the Julian day in the timezone for this Time object
return
the UTC milliseconds for the beginning of the Julian day
        // Don't bother with the GMT offset since we don't know the correct
        // value for the given Julian day.  Just get close and then adjust
        // the day.
        long millis = (julianDay - EPOCH_JULIAN_DAY) * DateUtils.DAY_IN_MILLIS;
        set(millis);
        
        // Figure out how close we are to the requested Julian day.
        // We can't be off by more than a day.
        int approximateDay = getJulianDay(millis, gmtoff);
        int diff = julianDay - approximateDay;
        monthDay += diff;
        
        // Set the time to 12am and re-normalize.
        hour = 0;
        minute = 0;
        second = 0;
        millis = normalize(true);
        return millis;
    
public native voidsetToNow()
Sets the time of the given Time object to the current time.
public native voidswitchTimezone(java.lang.String timezone)
Convert this time object so the time represented remains the same, but is
instead located in a different timezone. This method automatically calls
normalize() in some cases
public native longtoMillis(boolean ignoreDst)
Converts this time to milliseconds. Suitable for interacting with the
standard java libraries. The time is in UTC milliseconds since the epoch.
This does an implicit normalization to compute the milliseconds but does
not change any of the fields in this Time object. If you want
to normalize the fields in this Time object and also get the milliseconds
then use {@link #normalize(boolean)}.



If "ignoreDst" is false, then this method uses the current setting of the
"isDst" field and will adjust the returned time if the "isDst" field is
wrong for the given time. See the sample code below for an example of
this.



If "ignoreDst" is true, then this method ignores the current setting of
the "isDst" field in this Time object and will instead figure out the
correct value of "isDst" (as best it can) from the fields in this
Time object. The only case where this method cannot figure out the
correct value of the "isDst" field is when the time is inherently
ambiguous because it falls in the hour that is repeated when switching
from Daylight-Saving Time to Standard Time.



Here is an example where toMillis(true) adjusts the time,
assuming that DST changes at 2am on Sunday, Nov 4, 2007.


Time time = new Time();
time.set(2007, 10, 4); // set the date to Nov 4, 2007, 12am
time.normalize(); // this sets isDst = 1
time.monthDay += 1; // changes the date to Nov 5, 2007, 12am
millis = time.toMillis(false); // millis is Nov 4, 2007, 11pm
millis = time.toMillis(true); // millis is Nov 5, 2007, 12am





To avoid this problem, use toMillis(true)
after adding or subtracting days or explicitly setting the "monthDay"
field. On the other hand, if you are adding
or subtracting hours or minutes, then you should use
toMillis(false).



You should also use toMillis(false) if you want
to read back the same milliseconds that you set with {@link #set(long)}
or {@link #set(Time)} or after parsing a date string.
public native java.lang.StringtoString()
Return the current time in YYYYMMDDTHHMMSS format